I did try the themes but as you said that doesn't guarantee the show will be recorded.

If I go and find when the show is on and tell it to record everytime the show is on then if the shows time changes it won't get recorded. With the tivo I just pick the show tell it to record it everytime it's on and that's it I don't have to worry about it getting moved or when it's on.

Like mythbusters for instance discovery moves it around all the time so if I told it to record everytime it's on I would have to keep redoing it everytime the show moves. If I did a theme then it wouldn't always get recorded.

Most of the stuff I watch is on cable and they tend to rearrange the show times often so maybe it woudn't be a problem if I watched the networks.